Easy as ABC

Fill in the first letters of the alphabet on every row and every column exactly once. Some squares remain empty. To the right of the puzzle it is stated which letters it is about (A~D for example, means that we need to use A, B, C and D). Along the boundaries of the diagram clues are given about which letter you come across first from that side.

In some puzzles, the clues consist of a letter and a digit, rather than just a letter, for example "B2". This means that the B is the second letter encountered from that direction. More information.